Field of the Invention
The invention is directed to a heating platform and a printing apparatus and more particularly, to a heating platform and a 3D printing apparatus applying the heating platform.
Description of Related Art
Along with the progress in computer-aided manufacturing (CAM), manufacturers have developed the three-dimensional (3D) printing technology to rapidly fabricate an original design concept. The 3D printing technology is by meaning a collective term referring to a series of rapid prototyping (RP) techniques, and the basic principle is additive manufacturing, where a RP machine is used to form cross-sectional shapes of a workpiece in an X-Y plane through scanning, shift intermittently at a layer thickness in the Z coordinates, and ultimately form 3D objects. The 3D printing technology is applicable regardless of the geometric shapes, and the RP technology produces excellent outputs in particular for complex parts, which significantly saves efforts and processing time. The 3D printing technology is capable of presenting an object of a digital 3D model designed by means of computer-aided design (CAD) software in less time for a user to touch and actually feel the geometry of the model, or even to test the assembling capability of the parts and possible functions.
Taking a 3D printing apparatus utilizing a fused deposition modeling (FDM (method) for example, a thermal-plastic material is heated and melted, and then coated in a layer-by-layer manner on a substrate of the 3D printing apparatus, such that a 3D object is formed in the layer-by-layer manner after the thermal-plastic material is cooled, cured and dispensed. The substrate of such type of 3D printing apparatus has to be continuously heated during the manufacturing process of the 3D object to maintain a temperature of the substrate as being higher than a curing temperature of the thermal-plastic material so as to prevent the thermal-plastic material from being cooled too soon and cured. Additionally, the temperature of the substrate may be sensed by a temperature sensing element, such that a control unit can control the temperature of the substrate according to a sensing result of the temperature sensing element. Nevertheless, when the substrate is manufactured as having a larger area, temperature unevenness occurs easily on surfaces of the substrate, for example, the central portion of the substrate has a higher temperature, while the peripheral portion of the substrate has a lower temperature. Therefore, if the temperature sensing element adjusts the temperature of the substrate only according to the temperature in part of the substrate, the central portion of the substrate may be probably overheated, which cause the 3D object to be burnt, or the peripheral portion of the substrate may probably be excessively cold, which causes the 3D object to be unexpectedly cured.